The present invention relates generally to a system and method for randomly accessing stored compressed video footage or other continuous image footage and a field inspection system employing the method and system for randomly accessing stored compressed video footage. More specifically, the present invention relates to a field inspection system for acquiring, reviewing, and archiving field inspection video.
Most municipalities that are responsible for maintaining sewer systems, require that the periodic inspections of the sewer lines be accomplished by first having a field inspection crew videotape the inside of the sewer lines and then having an engineer review these video tapes to assess the condition and defects in the sewer lines and to recommend whatever actions are necessary to repair such defects. An example of a pipeline data collection and display system that may be used to obtain video footage of the interior of a sewer line is disclosed in U.S. Pat. No. 4,974,168. In this disclosed system, a field inspection crew positions a van 11 (FIG. 1) including the inspection equipment, close to a manhole entry 16 of a sewer line 15 to be inspected. First, the crew backwashes the sewer line, and then sets up the inspection equipment as shown in FIG. 1, by placing a surface roller assembly 18 at the opening of manhole entry 16 and placing a wind-up winch assembly 21 at the opening of an adjacent manhole entry 17. A tow cable 22 extending from wind-up winch assembly 21 is passed through a manhole down roller assembly 20 and connected to a monitoring device 14, which includes a video camera. A cable assembly 12 coupled at one end to electronic survey equipment 43 located in van 11, is passed down through surface roller assembly 18 and a manhole down roller assembly 19 and coupled to an opposite end of monitoring device 14. Having described the physical assembly of a typical field inspection system, the manner by which the video information is obtained, processed, taped, reviewed, and subsequently archived will now be described with reference to FIG. 2.
As the field inspection crew moves monitoring device 14 through the sewer line, the video footage obtained from the video camera is fed to a display device and monitored by an operator in van 11 (step 52). While monitoring the video footage, the operator prepares a handwritten logsheet identifying the suspected defects and anomalies and their location in the sewer line (step 54). Some of this information written on the logsheet may be entered on a keyboard such that the system may generate and overlay graphics showing this information on the video footage to which it pertains (step 56). The video footage is recorded on a video tape along with the overlaid graphics using a video cassette recorder (VCR) (step 58). Then after the field inspection crew has filmed the designated portion of sewer line 15, it sends the video tape and the handwritten logsheet to an engineer typically employed by the municipality (step 60).
The engineer's job is to review the field inspection videos supplied by the inspection crew and to recommend what action is to be taken to repair any confirmed defects or anomalies. To perform this task, the engineer will place the video tape in a VCR and review the logsheet to determine whether there are any suspected defects in the sewer line, provided of course that the logsheet is still with its associated video tape. Then the engineer fast-forwards, pauses, and rewinds the video tape to locate the video footage corresponding to each suspected defect indicated on the associated logsheet (step 62). Based upon the review of the video tape, the engineer writes a report identifying each defect and recommending a course of action to repair the defect (step 64). Provided the recommended course of action can be carried out within the municipality's budget, the municipality will accept bids from contractors to repair the sewer line (step 66). Then after a bid is accepted, a contractor will repair the sewer line in accordance with the engineer's recommended course of action (step 68) and the municipality will dispatch the field inspection crew to again video tape the repaired sewer line so that the engineer can review the contractor's work to ensure that the sewer line was repaired properly (step 70). After this process is completed, the logsheet, videotapes, and engineering reports are archived typically by placing the paper documents within the video tape slip cover along with the video tape and placed on a shelf (step 72).
The above described methodology is inefficient for several reasons. First, requiring an engineer to fast-forward and rewind the video tape to find those portions within the video that show the suspected defects listed on the logsheet is frustrating and time consuming for the engineer. Additionally, archiving of the video tapes and logsheets in this manner often results in the logsheets becoming lost or otherwise separated from their associated video tapes.